This document provides an overview of human-computer interaction and interaction design. It defines HCI as the study and practice of designing computers and technology that are easy to use, effective, and enjoyable for people. Interaction design aims to design interactive products and digital spaces that support human communication and interaction. The document outlines various principles of interaction design like visibility, feedback, consistency and affordances to guide the design of intuitive and usable interfaces. It emphasizes the importance of involving users and understanding their needs in the design process.

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CSE4107-Human Computer Interaction
Lecture 2: Interaction Design
Dr. Md. Sazzad Hossain, PhD (Japan)
Professor
Department of CSE
Mawlana Bhashani Science and Technology University
Email: sazzad@mbstu.ac.bd

2. What is human-computer interaction (HCI)?
• HCI is the study and the practice of usability.
• It is about understanding and creating software and other technology
that people will want to use, will be able to use, and will find effective
when used.
• HCI is the study of how people use computer systems to
perform certain tasks
• HCI tries to provide us with all understanding of the computer and the
person using it, so as to make the interaction between them more
effective and more enjoyable.

3. Humans, Computer and Interaction
The H Humans good at: Sensing low level stimuli, pattern
recognition,inductive reasoning, multiple
strategies, adapting “Hard and fuzzy things”.
The C Computers good at: Counting and measuring,
accurate storage and recall, rapid and consistent
responses, data processing/calculation, repetitive
actions, performance over time, “Simple and
sharply defined things”.
The I The list of skills is somewhat complementary. Let
humans do what humans do best and computers do
what computers do best.

4. Motivation: Why Care About People?
•Human - computer interaction (HCI)
• The study of the ways that people use computers
• Practice of making computers easier for people to use
•Is that possible?
• Yes
•It happens when people who design computers and
software keep in mind that they are designing for
other people

5. Different design Needs
Three broad categories of computer user:
1. Expert users with detailed knowledge of that particular
system.
2. Occasional users who know well how to perform the tasks
they need to perform frequently.
3. Novices who have never used the system before.
Users may well be novices at one computer application but
experts at another one, so users will belong to different
categories for particular computer systems.

6. What is interaction design?
• “Designing interactive products to support the way people
communicate and interact in their everyday and working
lives.”
• Preece, Sharp and Rogers (2015)
• “The design of spaces for human communication and
interaction.”
• Winograd (1997)
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7. Goals of interaction design
• Develop usable products
• Usability means easy to learn, effective to use and provide an enjoyable
experience
• Involve users in the design process
• Number of other terms used emphasizing what is being
designed, e.g.
• user interface design, software design, user-centered design, product
design, web design, experience design (UX)
• Interaction design is the umbrella term covering all of these
aspects
• fundamental to all disciplines, fields, and approaches concerned with
researching and designing computer-based systems for people
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8. HCI and interaction design
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9. Bad designs
Elevator controls and labels on the bottom row all look the same, so it
is easy to push a label by mistake instead of a control button
People do not make same mistake for the labels and buttons on the
top row. Why not?
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10. Good design
• Marble answering machine (Bishop, 1995)
• Based on how everyday objects behave
• Easy, intuitive and a pleasure to use
• Only requires one-step actions to perform core tasks
• http://viewpure.com/RgVbXV1krgU?start=0&end=0
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11. What to design
• Need to take into account:
• Who the users are
• What activities are being carried out
• Where the interaction is taking place
• Need to optimize the interactions users have with a product:
• So that they match the users’ activities and needs
• Bad design example: http://bolden.nl/
• Is this a clever design? Yes, definitely. But is this bad design? Absolutely!
• This is a great example of designing for the designer, rather than the user:
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12. Understanding users’ needs
• Need to take into account what people are good and bad at
• Consider what might help people in the way they currently
do things
• Think through what might provide quality user experiences
• Listen to what people want and get them involved
• Use tried and tested user-centered methods
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13. Working in multidisciplinary teams
• Many people from different backgrounds involved
• Different perspectives and ways of seeing and talking about
things
• Benefits
• more ideas and designs generated
• Disadvantages
• difficult to communicate and progress forward the designs being
create
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14. What do professionals do in the ID
business?
• interaction designers - people involved in the design of all the interactive
aspects of a product
• usability engineers - people who focus on evaluating products, using usability
methods and principles
• web designers - people who develop and create the visual design of websites,
such as layouts
• information architects - people who come up with ideas of how to plan and
structure interactive products
• user experience designers (UX) - people who do all the above but who may
also carry out field studies to inform the design of products
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15. The User Experience
•How a product behaves and is used by people in the
real world
• the way people feel about it and their pleasure and satisfaction when
using it, looking at it, holding it, and opening or closing it
• “every product that is used by someone has a user experience:
newspapers, ketchup bottles, reclining armchairs.” (Garrett, 2010)
•Cannot design a user experience, only design for a user
experience
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16. Why was the iPod user experience was such a
success?
•Quality user experience
from the start
•Simple, elegant, distinct
brand, pleasurable, must
have fashion item,
catchy names, cool, etc.
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17. What is involved in the process of interaction
design
• Establishing requirements
• Developing alternatives
• Prototyping
• Evaluating
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18. Core characteristics of interaction design
•Users should be involved through the development
of the project
•Specific usability and user experience goals need to
be identified, clearly documented and agreed at the
beginning of the project
•Iteration is needed through the core activities
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19. Why go to this length?
•Help designers:
• understand how to design interactive products that fit with
what people want, need and may desire
• appreciate that one size does not fit all
e.g., teenagers are very different to grown-ups
• identify any incorrect assumptions they may have about
particular user groups
e.g., not all old people want or need big fonts
• be aware of both people’s sensitivities and their
capabilities
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20. Are cultural differences important?
•5/21/2024 versus 21/5/2024?
• Which should be used for international services and online
forms?
•Why is it that certain products, like the iPod, are
universally accepted by people from all parts of the
world whereas websites are reacted to differently by
people from different cultures?
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21. Accessibility
• Degree to which a product is usable and accessible by as many
people as possible
• Focus on disability:
• Have a mental or physical impairment
• This has an adverse affect on their everyday lives
• It is long term
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22. Usability goals
• Effective to use (doing the right thing)
• How good a product is at doing what it is supposed to do
• Efficient to use (doing things right)
• Product supports users carrying out their tasks efficiently.
• Safety
• Safe to use
• Have good utility
• Product provides a right kind of a functionality so users can do what they need or want to do
• Learnability
• Easy to learn
• Memorability
• Easy to remember how to use
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23. User experience goals
Desirable aspects
satisfying helpful fun
enjoyable motivating provocative
engaging challenging surprising
pleasurable enhancing sociability rewarding
exciting supporting creativity emotionally fulfilling
entertaining cognitively stimulating
Undesirable aspects
boring unpleasant
frustrating patronizing
making one feel guilty making one feel stupid
annoying cutesy
childish gimmicky
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24. Usability and user experience goals
• Selecting terms to convey a person’s feelings, emotions, etc.,
can help designers understand the multifaceted nature of the
user experience
• How do usability goals differ from user experience goals?
• Are there trade-offs between the two kinds of goals?
• e.g. can a product be both fun and safe?
• How easy is it to measure usability versus user experience
goals?
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25. Design principles
• Generalizable abstractions for thinking about different aspects of
design
• The do’s and don'ts of interaction design
• What to provide and what not to provide at the interface
• Derived from a mix of theory-based knowledge, experience and
common-sense
• Visibility, Feedback, Constraints, Consistency, Affordance
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26. Visibility
• This is a control panel for an elevator
• How does it work?
• Push a button for the floor you want?
• Nothing happens. Push any other button? Still
nothing. What do you need to do?
• It is not visible as to what to do!
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27. Visibility
…you need to insert your room card in the slot by the
buttons to get the elevator to work!
How would you make this action more visible?
• make the card reader more obvious
• provide an auditory message, that says what to do
(which language?)
• provide a big label next to the card reader that
flashes when someone enters
• make relevant parts visible
• make what has to be done obvious
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28. Feedback
• Sending information back to the user about what has been
done
• Includes sound, highlighting, animation and combinations of
these
• e.g. when screen button clicked on provides sound or red highlight
feedback:
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29. Constraints
• Restricting the possible actions that can be performed
• Helps prevent user from selecting incorrect options
• Physical objects can be designed to constrain things
• e.g. only one way you can insert a key into a lock
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30. Logical or ambiguous design?
• Where do you plug the mouse?
• Where do you plug the
keyboard?
• top or bottom connector?
• Do the color coded icons help?
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31. How to design them more logically
(i) A provides direct adjacent
mapping between icon and
connector
(ii) B provides color coding to
associate the connectors
with the labels
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32. Consistency
• Design interfaces to have similar operations and use similar
elements for similar tasks
• For example:
• always use ctrl key plus first initial of the command for an operation –
ctrl+C, ctrl+S, ctrl+O
• Main benefit is consistent interfaces are easier to learn and use
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33. When consistency breaks down
• What happens if there is more than one command starting with
the same letter?
• e.g. save, spelling, select, style
• Have to find other initials or combinations of keys, thereby
breaking the consistency rule
• e.g. ctrl+S, ctrl+Sp, ctrl+shift+L
• Increases learning burden on user, making them more prone to
errors
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34. Internal and external consistency
•Internal consistency refers to designing operations to
behave the same within an application
• Difficult to achieve with complex interfaces
•External consistency refers to designing operations,
interfaces, etc., to be the same across applications
and devices
• Very rarely the case, based on different designer’s
preference
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35. Keypad numbers layout
• A case of external inconsistency
1 2 3
4 5 6
7 8 9
7 8 9
1 2 3
4 5 6
0 0
(a) phones, remote controls (b) calculators, computer keypads
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36. Affordances: to give a clue
• Refers to an attribute of an object that allows people to know
how to use it
• e.g. a mouse button invites pushing, a door handle affords pulling
• Norman (1988) used the term to discuss the design of
everyday objects
• Since has been much popularised in interaction design to
discuss how to design interface objects
• e.g. scrollbars to afford moving up and down, icons to afford clicking
on
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37. What does ‘affordance’ have to offer
interaction design?
• Interfaces are virtual and do not have affordances like physical objects
• Norman argues it does not make sense to talk about interfaces in terms
of ‘real’ affordances
• Instead interfaces are better conceptualized as ‘perceived’ affordances
• Learned conventions of arbitrary mappings between action and effect at the
interface
• Some mappings are better than others
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38. Activity
• Virtual affordances
How do the following screen objects afford?
What if you were a novice user?
Would you know what to do with them?
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39. Key points
• Interaction design is concerned with designing interactive
products to support the way people communicate and interact
in their everyday and working lives
• It is concerned with how to create quality user experiences
• It requires taking into account a number of interdependent
factors, including context of use, type of activities, cultural
differences, and user groups
• It is multidisciplinary, involving many inputs from wide-
reaching disciplines and fields
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